FIG. 1 illustrates a prior art low voltage lighting system 10 including a main supply 12 providing a main supply signal 14 representing, for example, the voltage 15 across output terminals 16, to a dimmer 20, which is an optional component that may be replaced with a simple switch. In the low voltage lighting system 10 illustrated in FIG. 1, dimmer 20 generates a dimmer signal 24 representing, for example, the voltage 25 across dimmer output 26, that has a lower average power than main supply signal 14. Dimmer 20 may, for example, cut the phase of main supply signal 14. The dimmer signal 24 is provided to an electronic transformer 30. The electronic transformer 30 converts dimmer signal 24 to a transformer output signal 34 representing, for example, the voltage 35 across transformer output 36 that provides a supply signal for a low voltage lamp 40, which draws a lamp current 42 from electronic transformer 30. Low voltage lamp 40 may be a halogen lamp, a light emitting diode (LED) lamp, or another type of lamp that operates on a low voltage supply, i.e., a supply producing a supply voltage of 12 VRMS (root mean squared) or less.
The electronic transformer 30 may include self-oscillating circuitry that requires a minimum current, referred to as the oscillating current, to self-sustain reliable oscillation. If the lamp current 42 is less than the oscillating current specified for electronic transformer 30, electronic transformer 30 may fail to operate reliably and low voltage lamp 40 may flicker or fail to illuminate.
The lamp current of halogen lamps is typically greater than the oscillating current specified for electronic transformer 30. LED lamps, however, are generally more efficient and have lower power ratings than halogen lamps of comparable luminosity. While higher efficiency and lower power consumption are generally desirable, the lamp current 42 associated with an LED lamp may be lower than the oscillation current specified for the electronic transformer 30.